Manufacture of glycol thioethers



Jan. 17, 1950 J. B. DAVIDSON ETAL h 2,494,610

MANUFACTURE oF GLYcoL THIoE'n-IERS Filed Feb. e, 1947 INVENTOR 505W gni/@50N z5 all/y /IY R mutua., CL, Auw

ATTORNEY Patented Jan. 17, 1950 MANUFACTUBE F GLYCOL THIOETHERS John B. Davidson and John F. Olin, Grosse Ile,

Mich., Aassignol-s to Sharples Chemicals Inc., a corporation of Delaware Application February 6, 1947, Serial No. 726,840 11 Claims. (Cl. 26o-609) 'Ihe present invention relates to condensation of aliphatic mercaptans containing from 6 to 24 carbon atoms with ethylene oxide and its equivalents to form glycol thioethers'. Compounds of this type are useful as surface active agents and?" intermediates in synthesis of other organic compounds. While the invention is applicable, in certain of its broader aspects, to condensation of ethylene oxide with mercaptans regardless of the ratio of ethylene oxide to mercaptan entering into the condensation reaction, it is concerned particularly with manufacture of compounds having the formula RS CH2CH2O) nCHzCHzOH, in which R, represents an alkyl radical having from 6 to 24 carbon atoms and n is a number greater than 2.

The fundamental equation with which the reaction of the invention is concerned in manufacture of compounds of the foregoing formula may be represented as follows:

An alkaline catalyst is used in promoting the condensation of the foregoing equation in the practice of the invention. In this connection there may be used, for example, an alkali metal hydroxide, oxide, alcoholate, mercaptide, or indeed any alkaline substance known to the art to be capable of catalyzing the condensation of ethylene oxide with mercaptans.

While important advantages may be attained in practice of the invention in condensation of mercaptans containing between 6 and 24 carbon atoms with ethylene oxide regardless of the structure of the mercaptan, it has particular value in condensation of tertiary alkyl mercaptans with ethylene oxide. Among the advantages attained by condensation of these and other mercaptans of 6 to -24 carbon atoms with ethylene oxide in practice of the invention are the following:

1. The amount of by-product formation is minimized, thereby improving the yield of desired thioether material useful as a surface active agent or for other purpose intended. By the practice of the invention, the formation of impurities imparting an unpleasant odor to the product. and other impurities causing a decrease in surface activity of the product and imparting a dark color to the product. is minimized.

2. A product of greater uniformity, both as to chemical constitution and physical state, is obtained. It is evident from the nature of the foregoing equation that the' product will comprise a. mixture of glycol thioether molecules of varying ethoxy content. This varying ethoxy content is undesirable, for it would be best to provide a product of uniform chemical composition having an ethoxy content optimum for the particular use to which the product is to be applied. By the practice of the invention, the gly- `col thioether product is must more nearly uniform in this regard than products of similar character obtainable by prior art procedure, and practice of the invention thus makes it possible to obtain a material which is more desirable for the surface active or other use to Which it is to be put, and a product may 'be obtained which is more nearly homogeneous as to physical state than products of this type heretofore available.

3. A product is obtained which is more stable than products of this type obtained by other processes.

In order to obtain the foregoing advantages in optimum degree in practice of the invention, the mercaptan is first condensed with a small amount of ethylene oxide (relative to that ultimately entering into the condensation 'reaction to form a surface active agent) at a temperature considerably lower than temperatures which have heretofore been used in effecting such condensation. In case a glycol thioether of higher ethoxy content is to be produced, a further quantity of ethylene oxide is thereafter added to the initial reaction mixture, and the condensation of this further quantity of ethylene oxide with the initial reaction product is preferably conducted at a substantially higher temperature than that of the initial reaction. The addition of this further quantity of ethylene oxide is preferably performed progressively as the reaction proceeds.

At the end of the condensation reaction, the alkalinity of the reaction mixture (due to the alkaline catalyst used) is reduced or eliminated by treatment of the reaction mixture with an acidic substance. A feature of the invention consists in control of the pH of the product. While this may be achieved by carefully controlled use of a strongr acid, a particular feature consists in the use for this purpose of a weak acid or acid salt, capable' of reducing the alkalinity and there- 4by providing a stable product while avoiding the danger of excess acidulation. Such excess acidulation is undesirable because of the fact that a product of too low pH is unstable, especially in the case of glycol thioethers derived from tertiary mercaptans. Tertiary mercaptans obtained by sulfhydration of polymerized olens yield glycol thioethel's which require especially careful handling in this connection, and by use of Weak 3 I acidulants. the danger cf destroying the stability of the product by excess acid-lation is avoided.

In the practice o! the invention. the acidulation ispreferably accomplished in the presence o! water, and the present invention may be accomplished with particular advantage by the addition oi water to the reaction mixture followed by contact of the resulting mixture with carbon dioxide to eifect acidulation.

After the acidulation has been accomplished, the reaction mixture is contacted with a stream of gas to remove volatile and odoriferous impurities. By control of the acidulating step to obtain a product which is substantially neutral prior to the removal of impurities by the gas treatment, this ilnal treatment may be accomplished without significant decomposition of the product.

Further features and advantages of the invention, and the details by which it is practiced, will be evident from a reading of the following detailed description in the light of the attached ow sheet, which illustrates one embodiment of practice of the invention in continuous operation.

In the practice of the invention as illustrated in the now sheet, sodium methylate catalyst from storage vessel i may be passed into contact with mercaptan from storage vessel 2 in mixing kettle 3. The resulting mixture is thoroughly agitated in kettle 3 and heated to a temperature between 60 and 70 C. under vacuum. The sodium methylate reacts with the mercaptan to form a mixture of mercaptan and mercaptide, and the methanol released by this reaction is removed by application of vacuum.

The mercaptan-mercaptide mixture in kettle I is next cooled to room temperature and fed by pump into conuence with a stream of ethylene oxide fed by pump 6 from storage Vessel 4. From the zone of confluence, the resulting reaction mixture passes through reaction system 1--i2. The ilrst unit 'l of this reaction system may comprise a steel coll 200 ft. long and 1/3 inch in internal diameter, and this coil may be immersed in a bath of circulating cold water. The requisite amount of liquid ethylene oxide necessary to form the desired polyglycol ether reaction product may be distributed in ilve approximately equal streams by the pump 6 to the inlets of a series of reactor coils of the type of coil 1. The coils of reaction unit B-II may each consist of a steel coil 300 it. long and inch in internal diameter immersed p in a bath of boiling water. Unit l2 may comprise a steel coil 250 ft.long and inch in internal diameter immersed in boiling water. It will be noted that no ethylene oxide is introduced directly into the mixture entering this last coil, as this coil is designed to provide for substantial completion of the condensation of any ethylene oxide failing to react in the preceding units.

Material discharged from coil l2 passes through a pressure release valve i3 into the upper section of vacuum stripper Il which may be a stripping' column provided with a vacuum connection through which any ethylene. oxide is removed. A stream of water is metered into the stripped product passing from the bottom of the column il; of water may, for example, be added to the reaction mixture at this point. The diluted thioether product is next passed by pump I5 into the upper section of va packed column I6 and ilows downward into countercurrent contact with a sufil. the product is forced by pump I1 throush heater Il and is introduced at about 105 C. into the upper section of a packed column I9 wherein it iiows downward countercurrent to slightly superheated steam. From the bottom of deodorlzing column is, the product is fed by pump 20 through a filter press 2| which ei'lects removal of solid particles.

In thel use of a reaction system as described above in manufacture of a reaction product corresponding to the average formula for example, by condensing with ethylene oxide tertiary dodecyl mercaptan obtained by sulfhydration of tri-isobutylene, the following details of procedure may be practiced. The mercaptan is first mixed with an amount of sodium methylate or the like which may constitute from 1 to 10% of a molecular equivalent of the mercaptan. After mixing and removal of methanol, as described above. the mercaptan containing sodium mercaptide as catalyst is pumped to reaction unit l. An amount of ethylene oxide which may comprise from 0.5 to 3 molecular equivalents of the equivalents of the mercaptan is pumped into coniluence therewith and into the unit 1. The reaction mixture passing through unit 'I is maintained at a temperature below 75 C., and preferably between 0 and 65 C. during passage through the coil of that unit, by the cooling water. An amount of ethylene oxide in excess of 0.5 molecular equivalent, and usually about 1 molecular equivalent, will condense with the mercaptan in this first reaction unit.

The further quantity of ethylene oxide necessary to complete the reaction to form a product having an average of the desired number of (CHaCHzO) radicals is passed into the reaction mixture in a plurality of separate streams by the pumps i. While considerable latitude is permissible in this connection, best results may be attained by dividing the ethylene oxide introduced into units 8-H into equal parts and concient stream of carbon dioxide introduced toward i the bottom of the column to bring about neutralization of alkaline constituents. p From the bottom of the neutralizing column Ain the unit 'I is due both to the instability 0f the mercaptan and to the high velocity and exothermic nature of the initial reaction. Once the mercaptan has reacted with a molecular equivalent of ethylene oxide, the resulting hydroxy -ailml thioether can be subjected to higher temperatures in the presence of ethylene oxide without deleterious results, and it is desirable that the temperature be higher in the secondary reaction zone in order to insure reasonably rapid completion of the reaction. Use of similar temperatures 'inthe initial reaction zone, on the other hand, would result in formation of undesiredl byproducts and manufacture of a thioether product of inferior quality as to color, odor and uniformity of chemical composition. When boiling water is used under atmospheric pressure as the heat exchange medium for units 8-i2, the temperature of the reaction mixture in this zone will be maintained at about 100 C. Regardless of the partlcular details of apparatus and operation. however, it is desirable that the reaction mixture be maintained between 85 and 150 C. during this portion of the reaction, and preferably between 90 and 120 C.

While the invention has been illustrated in connection with an operation in which excess ethylene oxide is stripped from the reaction mixture before the reaction product is contacted with Water, the water may be added prior to the stripping operation without serious deleterious result. It is desirable, however, that the ethylene oxide be removed before addition of the water.

By adding the water prior to acidulation by treatment with a gaseous acidic substance such as carbon dioxide, the rate of the acidulating reaction is greatly increased, and by adding a sufficient quantity of water (e. g., the salts formed upon acidulation are dissolved, and remain in solution in the reaction product. These salts may be removed from the reaction product by the procedure as illustrated, by use of a smaller quantity of water. When it is desired to obtain a substantially anhydrous reaction product substantially free of salts, this may be accomplished by use of an amount of water suicient to convert the catalyst to alkali metal hydroxide, but insuicient to dissolve the carbonate and bicarbonate salts formed by acidulation by treatment with carbon dioxide. The quantity of water added for this type of operation should not be substantially greater than the amount which will be associated with the salt (in the form of water of crystallization or otherwise) and removed therewith upon subsequent separation of the salt, as for example by filtration, which is preferably performed prior to deodorization in this embodiment. This may be accomplished by use of an amount of water constituting between one and ten molecular equivalents of the catalyst.

While the invention has been described in reference to an operation in which water is added separately prior to acidulation, the water may be added in the form of diluent for the acidulant, if desired. As a further alternative, the step of adding water may be entirely omitted, although as noted above, there is advantage in use of water to speed up acidulation.

Various aciduating agents may be used in lieu of carbon dioxide. Regardless of the particular acidulating agent used, it is advantageous to control the nature and/or amount of the acidic substance employed to provide a product which has a pH between 5 and 9 as measured in 10% aqieous solution. By control of the pH of the product within these limits, there is obtained a thioether reaction mixture which is stable during the subsequent deodorization and use. A feature of the invention consists in use of an acidic substance having a primary ionization constant between lil-2 and 10-9. By use of an acidic substance of this character, the control of the pH of the product can be attained without difculty. Among the acidic substances which may be used to advantage in practice of the invention are carbon dioxide, acid clays, sodium bisulfate, and fatty and other carboxylic acids.

While the treatment of the acidulated product with steam or other gas to remove volatile and odoriferous impurities provides a product which is more desirable than would otherwise be obtained, this nal treatment may be omitted if desired. As noted above, however, the -product should be adjusted as to pH by treatment with an acidic'substance, if the step of deodorization is odorizing operation at a temperature above 50 C.

The deodorization may be accomplished, for example, by contacting the product with air, nitrogen or hydrogen in place of steam as illustrated, said contacting being accomplished either by blowing of steam or gas through a body of the `heated product or alternatively by passing said y, heated product through a suitable column in countercurrent contact with the stream of the gas.

In the foregoing discussion, we have considered an embodiment of the invention in which the successive steps in the manufacturing operation are performed during flow of the reaction mixture continuously. Important advantages are derived from this type of operation. The passage of the reaction mixture continuously through a conduit in which the reaction takes place insures intimate contact f the reactants in successive zones of relatively small cross-sectional area. This facilitates control of the reaction by improving heat control and by minimizing the presence of large excesses of ethylene oxide in any one zone of the reaction. It thus minimizes formation of byproducts and formation-of a reaction mixture including reaction products which vary widely as to number of (CI-I2CH2O) radicals. By operating continuously and introducing the ethylene oxide progressively as illustrated, these advantages are attained to an even greater extent by continuous operation than would otherwise be possible.

While, as noted above, continuous operation provides important advantages in practice of the invention, it is possible to practice features of the invention to advantage in a batch operation. Thus, the feature of conducting the initial reaction at a relatively low temperature and thereafter completing the reaction by operation at a higher temperature yields important advantages Whether conducted continuously or batch-wise.

While the feature of progressive introduction of the ethylene oxide into the reaction mixture, conducted continuously or batch-wise, provides decided advantages as to operating technique and quality of product, this feature may also be eliminated, and the entire quantity of ethylene oxide introduced at the start of the reaction. It should be noted, however, that unusual precautions are necessary in control of the temperature if this type of operation is adopted, and that the progressive introduction of the ethylene oxide makes it possible to conduct the reaction more rapidly with adequate control, and with elimination of many of the difficulties which would be inherent in a process in which the entire quantity of ethylene oxide is introduced at the outset.

While the invention has been described with reference to an operation 'in which a large stoichiometric excess of ethylene oxide is ultimately condensed with the mercaptan, it should be understood that the feature of use of an unusually low temperature in the initial condensation step provides important advantages even in case it is desired to terminate the reaction at a stage at which the principal reaction product is the beta-hydroxyethyl thioether, or a product of condensation of from 1 to 3 ethylene oxide radicals with the mercaptan.

While the invention has been described pri- The process is conducted in an apparatus having the arrangement illustrated in the accompanying diagram. Two pounds of sodium methylate and 165 pounds of tert-dodecyl mercaptan (prepared by sulfhydratlon of triisobutylene) are mixed in kettle 3 for 30 minutes at a temperature of 65-75 C. and under a vacuum of 27 inches.

The resulting solution, containing 4.5 mol per cent of sodium dodecyl mercaptide, is cooled to room temperature and is reacted with ethylene oxide in the following manner.

The mercaptan-mercaptide solution is pumped continuously at a rate of 6l lbs. per hr. together with ethylene oxide at a rate of 21.6 lbs. per hr. into a coil 1, comprising 200 ft. of 1/4 in. steel tubing, immersed in a bath of Water at C.

The eiiiuent is then passed successively through four coils 8-ll of 1,/2 in. internal diameter which are immersed in boiling Water baths, the reac- I tion stream being admixed with an additional 21.6 lb. per hr. of ethylene oxide at the point oi ingress to each of said coils. The eiliuent from coill I, which comprises predominately the polyglycol thioethers in admixture with minor proportions of the corresponding sodium alcoholates and ethylene oxide, is further reacted at 100 C. in unit I2, a coiled steel tube 250 ft. long and 3A in.

.inA diameter, to effect substantially complete utilization of the ethylene oxide.

`The resulting hot product-stream is freed of any remaining traces of ethylene oxide by application of vacuum and is pumped together with 10 lbs. per hr. of water to the upper section of the packed, neutralizationv column I6 wherein it descends countercurrent tol a flow of 1 lb. per hr.

of carbon dioxide.

- The nearly neutral solution is then heated to Y 105 vC. and is subjected at normal pressure (in an 8`tray, bubble-cap column I9) to countercurrent 8 dration of tetraisobutylene) is reacted with 108 lbs. per hr. of ethylene oxide and the product is stabilized and purined as described. It is an excellent emulsifying agent and has good detergent and wetting properties.

EXAMPLE 3 Teri-nonyZ-pentaglpcol thioether A A 4.5 mol per cent solution of sodium nonyl mercaptide in nonyl mex-captan (obtained by sulfhydration of propylene polymer) is prepared and is reacted at a rate of 'I8 lbs. per

" hr. with 108 lbs. per hr. of ethylene oxide in tive ting agent.

stages by the procedure ofExample 1. After purification ofthe resulting crude in the manner described, a nearly odorless clear liquid product is obtained having an average of 5.1 ethoxy units per mol. It is a very effective wetting agent.

EXAMPLE 4 Tert-dodecylpentadecaglycol thioether A procedure substantially similar to that employed in Example 1 is followed in condensing ethylene oxide with tert-dodecyl mercaptan. In this instance, however, a. solution containing 8 mol per cent of the sodium mercaptlde is prepared and is pumped at a rate of 51 lbs. per hr. into confluence with a total .of 128 lbs. per hr. of ethylene oxide, the latter being introduced in five separate streams. The product is puried in the manner described, and is found to contain an average of 14.7 ethoxy units per mol. It is an excellent detergent and a moderately good wet- EXAMPLE 5 Sec-octyl-octaglycol thioether the latter being derived by sulfhydration of the contact'with a ow of steam, the latter beinginp troduced at 150 C. at a rate of 275 lbs. per hr. Removal of undissolved carbonatos, scale, etc. is accomplished in a final filtration step.

The product thus obtained is a neutral,l clear,

.viscous oil,.light yellow in color and practically without odor, and has an averaseethoxy con-,

Y tent of '7.8 mois per mol of polyglycol thioether.

It enters readily into solution with vwater at all `concentrations and shows a tendency to gel only at concentrations in Ythe neighborhood of 50%. Standard launderometer and Draves tests, as well as tests in actual service, indicate its excellent wetting, detergent and grease-dispersing properties. Storage of samples of the product for a period of two months gives no perceptible diminution in activity. EXAMPLE 2 Tert-hexadecyl-dodecaglycol thiOe-ther By the procedure of Example 1, 52 lbs.per hr.

appropriate fraction of a gasoline synthesid from a natural gas source. In this instance the mercaptide concentration amounts to 2 mol per cent based on mercaptan, and the rate of flow of the mercaptan is adjusted to provide a contact period of 55 minutes in the reaction system. Neutralization and deodorization is accomplished in the described Vmanner to provide a stable oily product of good appearance and odor and having a high degree of surface activity.

EXAMPLE e Tera-aodeeyl-tetragiycoz thioether Tertiary dodecyl mercaptan and 50% sodium hydroxide are contacted at C. in vacuo to provide an anhydrous solution containing 3 mol .per cent of the mercaptide. The mixture is cooled ameter and is immersed in a bath of boilim water. The reaction period in the first coil is i minutes and in the second coil is 20 minutes The eiiiuent from the second reactor, whicl contains substantially no free ethylene oxide `is diluted with 0.1 proportion of water am is circulated at about .50 C. through a plate am frame lter press precoated with Retrol (an ach clay) until the pH of the product, 'as measured i1 10% aqueous so1ution, is reduced to a value be 9 tween 6 and 1. The product, though having a mildly unpleasant odor, undergoes no apparent degradation at room temperature in a period of six months. It is particularly eiectivein promoting contact between petroleum oils and water or moist surfaces.

EXAMPLE 7 Tert-dodecyl-octaglycol thz'oether The procedure of Example l is followed in all respects with the exception of the neutralization step. In this instance neutralization is accomplished by treating the aqueous solution of the crude polyglycol thioether with glacial acetic acid (2.1 lbs. per hr.) in lieu of carbon dioxide. The solution which, when diluted, is almost neutral to pH paper is subjected to the deodorization step of Example 1. The resulting octaglycol thioether is stable and odor free.

EXAMPLE 8 Tert-dodecyl-octaglycol thoether A crude reaction mixture prepared in accordance with the procedure of Example l is diluted with water introduced prior to the the neutralization step at the rate of 3 lbs. per hr. The resultant is then neutralized with carbon dioxide in the described manner and is filtered immediately thereafter. The major proportion of the water and the carbonates are thus eliminated in the form of a moist, partially hydrated cake to provide a substantially anhydrous and salt-free product. The resulting polyglycol thioether is especially suitable for blending with fatty acid 3 soaps and with other detergent and wetting compositions in uses requiring the absence of inorganic salts.

EXAlVIPLE 9 Tert-ecosyl-dodecaglycol thz'oether 0.5 lb. mols per hr. of tcrt-eicosyl mercaptan (derived by sulfhydration of petene-2 tetramer) and 12 lb. mols per hr. of ethylene oxide are condensed continuously in the presence of a catalytic quantity of the corresponding potassium mercaptide, and the product is neutralized and deodorized, substantially in accordance with the procedure of Example 1.

EXAMPLE 10 Tert-dodecyl-dodecaglycol thz'oether The crude polyglyco1 thioether derived by the condensation of tert-dodecyl mercaptan with 12 molar equivalents of ethylene oxide at 100-120 C. in the presence of the corresponding sodium mercaptide is almost black and has a strong, objectionable o dor. It is made substantially neutral by treatment with water and carbon dioxide and is thereafter heated to 110 C. and is blown with superheated steam for 15 minutes. The resulting product is still dark in color but is almost odorless and does not diminish in surface activity over a period of six months.

EXAMPLE 11 Tert-dodecyl-beta-hydroxyethyl sulfide 7.5 gram mols of tert-dodecyl mercaptan and 0.1 mol of its sodium mercaptide is placed in a two-gallon, stainless steel autoclave which is then freed of air by application of vacuum. While the temperature of the reactants is maintained below 60 C., 7.8 gram mols of ethylene oxide is introduced gradually over a period of 15 minutes. The resulting product, after being freed of 1111- reacted ethylene oxide, consists essentially of the desired glycol thioether in the form of a light amber oil. It may be puried by extraction or by distillation at reduced pressure, or polyethoxy derivatives may be prepared by reaction of the crude material with a further quantity of ethylene oxide at temperatures above 85 C.

Various modications are available to persons skilled in the art, and we do not therefore wish to be limited except by the scope of the following claims.

We claim:

l. In a process for the condensation of a mercaptan with ethylene oxide in the presence of a catalyst for said condensation, the steps comprising iiowing a stream originally containing said mercaptan, said catalyst and at least 0.5 molecular equivalent of ethylene oxide based on mercaptan through an initial reaction zone maintained under temperature conditions below 75 C. but suiciently high to initially condense ethylene oxide with said mercaptan, and thereafter flowing said stream with ethylene oxide present through a succeeding reaction zone maintained under temperature conditions between 85 C. and 150 C. to further condense ethylene oxide in said stream.

2. In a process for the condensation with ethylene oxide of a tertiary alkyl mercaptan containing between 6 and 24 carbon atoms per molecule and derived from a polymerized olen, in which condensation an alkaline catalyst for said condensation is employed to assist said condensation, the steps comprising ilowing a stream orig- 5 inally containing said mercaptan, said catalyst and at least 0.5 molecular equivalent of ethylene oxide based on mercaptan through at least two successive reaction zones, in the rst of which temperature conditions are maintained below 75 C. but suillciently high for initial condensation to take place between said mercaptan land said ethylene oxide and in a succeeding one of which temperature conditions are maintained between 85 C. and 150 C., maintaining the reactants 45 of said stream in said first reaction zone for a time lsuiiicient to initially condense at least 0.5

molecular equivalent of ethylene oxide based on mercaptan with said mercaptan, and thereafter ilowing said stream with ethylene oxide present 50 through said succeeding reaction zone to eilect further condensation of ethylene oxide in said stream.

3. The process of claim 2 in which a separate stream of ethylene oxide is combined with said stream of reactants downstream from said first reaction zone, and in which said combined streams are reacted in a reaction zone which is downstream from the said rst reaction zone.

4. In a process for the condensation with etho ylene oxide of a teritiary alkyl mercaptan con taining between 6 and 24 carbon atoms per molecule and derived from a polymerized olefin, in

which condensation an alkaline catalyst i'or said condensation is employed to assist said conden- 05 sation, the steps comprising maintaining a owing stream originally containing said mercaptan, said catalyst and from 0.5 to 3 molecular equivalent of ethylene oxide based on mercaptan under temperature conditions maintained between 0 C. and 65 C. for a time suiiicient to react at least 0.5 molecular quivalents of ethylene oxide based on mercaptan with said mercaptan, thereafter combining a separate stream of ethylene oxide with said rst-mentioned stream and maintaining the reactants of said combined streams under temperature conditions maintained between 85 C. and 150 C. for a time suilicient to effect desired further condensation therein.

5. The process of claim 4 in which the tertiary alkyl mercaptan is derived from tri-isobutylene.

6. The process of claim 4 in which approximately one molecular equivalent of ethylene oxide based on mercaptan is reacted with said mercaptan in the initial reaction.

'i'. The process of claim 6 in which the initial reaction is carried to substantial completion.

8. The process of claim 4 in which a large stoichiometric excess oi ethylene'oxide is ultimately condensed with said mercaptan.

9. The process oi claim 8 in which from 0.01 to 0.1 molecular equivalent of catalyst based on mercaptan is employed.

10. The process of claim 9 in which a plurality of reaction zones are employed downstream from the first reaction zone, and in which a separate stream of ethylene oxide is combined with said mst-mentioned stream at each or more than one of said downstream reaction` zones.

11. In a process for the condensation of a mercaptan with ethylene oxide with the aid of a catalyst for said condensation, the steps com- 12 prising combining said mercaptan, said catalyst and said ethylene oxide to eiiect initial condensation between said mercaptan and said ethylene oxide, maintaining the temperature ot the reaction mass below '75 C. during said initial condensation, thereafter subjecting the reaction mass with unreacted ethylene oxide present to temperature conditions between 85 C. and 150 C. to eiect condensation of ethylene oxide with said initial condensation product.

JOHN B. DAVIDSON.

JOHN F, OLIN.

REFERENCES CITED The following vreferences are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,129,709 Schuette et al Sept. 13, 1938 2,205,021 Schuette et al. June 18, 1940 2,392,103 Schlosser et al. Jan, 1. 1946 FOREIGN PATENTS a Number Country Date 794,830 France Dec. 26, 1935 

1. IN A PROCESS FOR THE CONDENSATION OF A MERCAPTAN WITH ETHYLENE OXIDE IN THE PRESENCE OF A CATALYST FOR SAID CONDENSATION, THE STEPS COMPRISING FLOWING A STREAM ORIGINALLY CONTAINING SAID MERCAPTAN, SAID CATALYST AND AT LEAST 0.5 MOLECULAR EQUIVALENT OF ETHYLENE OXIDE BASED ON MERCAPTAN THROUGH AN INITIAL REACTION ZONE MAINTAINED UNDER TEMPERATURE CONDITIONS BELOW 75* 